Method of refining blended lubricating oils



Patented July 12, 1938 ATENT OFFlCE METHOD or REFINING BLENDED LUBRI- CATING OILS Eddie M. Dons and Dwight B. Mapes, Tulsa, Okla.,

assignors to Mid-Continent Petroleum Company, Tulsa, Okla, a corporation of Delaware Application July 10, 1936, Serial No. 89,921

Claims.

This invention relates to methods of blending mineral oils. Prior to this invention, in the manufacture of blended lubricating oils, heavy residuum stocks have been mixed with overhead distillates and the resultant blend is then treated with sulfuric acid. This old practice of simultaneously treating constituents of the blends is ordinarily followed in treating distillatesblended with reduced crude petroleum containing a substantial percentage of asphaltic material.

Our study of this old practice has shown that the asphalt-lo material in the crude residuum consumes a very large percentage of the acid, which considerably reduces the efficiency of the acid in treating other constituents of the blend.

An object of the present invention is to so treat the constituents of blended oils that the acid will very effectively perform its functions in treating the different kinds of materials. Briefly stated, instead of beginning with the step of treating the blended materials, we begin by selecting the frac-' tion thatis most difficult to treat, for example, an

asphalt-containing residuum, and subject it to the action of sulfuric acid. After removing the acid sludge, the treated oil is blended with the distillate stock, and the resultant blend of treated and untreated oil is then treated with additional acid.

In a specific example, hereafter set forth, we will show how the new method (compared with the above-mentioned ol-d practice) may be employed to reduce the quantity of. acid, as well as the temperature of the acid treatment, and at the same time obtain improved results.

With the foregoing and other objects in view,

the invention comprises the novel method hereinafter more specifically described and shown in the accompanying drawing, which illustrates one form of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications within the scope of the claims hereunto appended.

The drawing is a diagrammatical view of a system embodying the features of this invention.

As an illustration of the different kinds of oils to be blended, we haveshown a tank I for residuum, which may be reduced crude petroleum containing a substantial percentage of asphaltic material, and a tank 2 for an overhead distillate stock to be blended with the residuum. A desirable lubricating oil can be produced by blending materials of this kind.

3 designates a supply of sulfuric acid, and 4 is a chamber wherein the residuum from tank I is treated with the acid. In the preferred form of the invention, the stock to be treated is mixed with a diluent or solvent from a supply tank 5. This diluent is preferably a normally liquid hydrocarbon of the paraffin series, or cyclo-paraflin series, substantially free from constituents that react with sulfuric acid. It may be selected from pentane, hexane, heptane, or other members of either of said series. Mixtures of such hydrocarbons having about 3 to 8 carbon atoms may be employed as a solvent or diluent.

If desired, a normally gaseous hydrocarbon diluent, such as propane, butane, etc., may be employed, but in this event, the system should be designed to operate under a pressure high enough to retain the diluent in a liquid condition.

The residuum tank I is provided with a discharge pipe 6 connected to a pipe I which leads to the acid treater 4, a mixer 8 being located in the pipe line I. The diluent tank 5 is provided with a discharge pipe 9 leading to the pipe 'I. The acid receptacle 3 is connected to the pipe I by means of a pipe I0.

The residuum and diluent are united in the pipe I which receives acid from the pipe l0, and after passing through the mixer 8, these materials enter the chamber 4, where the acid sludge settles to the bottom, and is withdrawn through a discharge pipe ll.

The acid-treated solution, discharged from the top of the chamber 4, flows through pipe 12 to a pipe !3 leading to a mixer I4 which discharges through a pipe l5 to a chamber Hi.

The acid receptacle 3 is provided with a discharge pipe I I connected to the pipe I3. The distillate tank 2 discharges through a pipe l8 leading to the pipe l2.

It will now be understood that the treated solution passing from the pipe I2 is mixed with distillate from tank 2, and acid from the receptacle 3, and that the resultant mixture is discharged into the chamber I6. The acid sludge is discharged through a pipe I9 at the bottom of the chamber l6, while the diluted blend of residuum. and distillate is discharged from the top, through a pipe 20. This blend of lubricating oil stocks may be further refined by contacting with clay which serves as a neutralizing and decolorizing agent.

As a specific illustration of one form of the invention, we will refer to the manufacture of a L blended lubricating oil wherein 40 per cent of the blend was a reduced crude petroleum from the Mid-Continent field, having a Saybolt universal viscosity of 122 at 210 F., and containing a sub- Stantial proportion of asphalt and other impurities to be removed by the acid. The other constituent, amounting to per cent of the blend, was an overhead distillate from a similar crude oil.

The reduced crude, or residuum, diluted with 2%; parts of pentane to one part of the residuum, was treated with about 14 pounds of 98 per cent sulfuric acid per barrel of the residuum. The temperature of this acid treatment was F. to F.

The resultant acid-treated solution was mixed with the distillate to form a blend, which was then treated with ten pounds of 98 per cent sulfuric acid per barrel of oil in the blend. The acid-treated blend diluted with pentane, which may be regarded as the material discharged through the pipe 20, was then contacted with clay at a temperature of 375 F., thereby subjecting the blend to a neutralizing and decolorizing operation, and at the same time distilling the pentane, which is condensed and recovered. In using three fourths of a pound of clay per gallon of the blended oil, the product had a 2% Tag. Rob. color.

An ordinary commercial practice in treating the above mentioned oil stocks consists in treating the entire blend of residuum and distillate at a temperature of 120 F. to 130 F., using thirty-eight pounds of 98% sulfuric acid per barrel of the blend, and thereafter contacting the acid-treated blend with 1%; pounds of clay per gallon of the blend, to obtain a Tag. Rob. color of 2 to 2.5.

In the specific example of the new method we obtained a better color (2% instead of 2 to 2.5), using less acid (a total of about 15.6 pounds per barrel of the blend instead of 38 pounds), while treating at 80 F. to F., instead of F. to F., and in the contacting operation we used three-fourths of a pound of clay per gallon of blend, instead of 1%; pounds. We thus obtained a substantial improvement at each stage of the operation, and it will, of course, be understood that corresponding results can be obtained in treating various other kinds of blends, especially combinations of residuums and distillates to produce blended lubricating oils.

We claim:

1. In the art of refining blended lubricating oils, the steps which comprise treating a viscous petroleum residuum with sulfuric acid, thereafter adding a less viscous lubricating oil distillate to the treated viscous oil, and treating the 5 combined constituents of resultant blend with additional sulfuric acid.

2. In the art of refining blended lubricating oils, the steps which comprise treating a viscous petroleum residuum stock with sulfuric acid, re- 10 moving the resultant sludge, adding a less viscous lubricating oil distillate to the treated viscous residuum, treating the combined oils with sulfuric acid, and separating acid sludge from the treated blend of residuum and distillate. 15

3. In the art of refining blended lubricating oils, the steps which comprise diluting a petroleum residuum with a normally liquid hydrocarbon diluent selected from the parafiin series and cyclo-paraffin series, treating the diluted residuum with sulfuric acid, mixing the treated solution with a lubricating oil distillate, treating the diluted oils with sulfuric acid, and removing the diluent from the treated blend of residuum and distillate.

4. In the art of refining blended lubricating oils, the steps which comprise diluting a viscous petroleum residuum with a liquid hydrocarbon diluent selected from the parafiin series and cyclo-paraffin series, said diluent being substantially free of constituents that react with sulfuric acid, treating the diluted residuum with sulfuric acid, mixing the treated solution with a less viscous lubricating oil distillate, treating the resultant diluted oils with sulfuric acid, and 85 thereafter removing the diluent from the treated blend of distillate and residuum.

5. In the art of refining blended lubricating oils, the steps which comprise diluting a viscous petroleum residuum with pentane, treating the diluted residuum with sulfuric acid, mixing the acid-treated solution with a lubricating oil distillate, treating the mixture with sulfuric acid, and removing the pentane from the treated blend of residuum and distillate. '45

EDDIE M. DONS. DWIGHT B. MAPES.

cERTrLFIoATEoFcoRBEoTIoN Patent Non 2,12 ,50 July 12, 1958.

. EDDIE M. DONS, ET AL It is hereby certified that error appears in'the above, numbered patent requiring correction as follows: In the preambleto the grant, name of assignee, for "MID-CONTIENT PETROLEUM COMPANY read MID-CONTINEN'I' PETRO- LEUM CORPORATION; and line 15 of the grant and in the heading to the, printed specification, for .Mid-Continent Petroleum. Company" read Mid-Continent Petroleum Corporation, as shown by the record of-assignments in this office; and that the saidLetters Patent should'be read with this correction therein that the same may conformlto the record of the case in the Patent Office Signed and sealed this hth day of October, A; D. 1958.

Henry Van Arsdale (Seal) Acting Oommissioner of Patents, 

